Recently, Daye Electric Power Engineering Co., Ltd. invited the UHV power after-sales service team to provide technical support and conduct insulation withstand voltage tests for 14 cables of a photovoltaic substation in Daye.

Before going to the test site, UHV technicians asked the site personnel about the specific parameters of the cable, and learned that the rated voltage of the cable is 35kV, the shortest is more than 100 meters, and the longest is 3km. According to these parameters, the technicians chose to use the UHV-540kVA/270kV series resonant withstand voltage test device.

At noon on the same day, the technicians arrived at the test site. Subsequently, according to the test environment of the site, the technicians began to assemble the test equipment, and at the same time, according to the cable parameters provided by the on-site personnel, the reactor was reasonably connected in series and parallel and the cable was tested for withstand voltage. After half an hour of on-site test environment construction and test equipment assembly, the preparatory work in the early stage of the test was successfully completed.

Before the start of the withstand voltage test, the insulation test of the cable should be carried out, and the withstand voltage test can be carried out only after the insulation test is passed. Technicians used the BC2010 insulation resistance tester to test the A, B, and C phases of the cable respectively, and the test results showed that the insulation performance of the cable was very good, and the withstand voltage test could be carried out.

Next, the technicians officially began to test the withstand voltage of the cable. According to the GB50150-2021 power handover test regulations, when the AC withstand voltage test of 35kV power cable is done, the test voltage is 2U0, and the test time is 60min. Subsequently, the technician started the withstand voltage test after powering on the test equipment, set the test voltage to 52kV, and set the time to 60min. Once the equipment is up and running, the technician simply waits for the test to complete.

Because it is a newly installed cable, the whole test process is relatively smooth, the cable in the process of withstand voltage did not appear obvious discharge phenomenon, after a three-day on-site operation, the withstand voltage test of 14 cables was finally successfully completed. In the end, according to the entire test process, the technicians judged that the 14 cables were qualified and could be put into operation.